1. Field of the Invention
The present invention relates to a control arm applicable to a suspension system provided with multilinks. More particularly, the present invention relates to a control arm of a multilink suspension system control arm which can drain foreign materials input through a jig hole for manufacturing the control arm through a drain hole easily.
2. Description of Related Art
A suspension system for a vehicle is disposed between a vehicle body and a wheel, and connects two rigid bodies by using one or more links.
An upward or downward load transmitted from a road to the wheel is supported by a spring and a hydraulic pressure shock absorber, and a load applied to other directions is supported by harmonizing high stiffness and flexibility. Therefore, the suspension system mechanically harmonizes a relative movement between the vehicle body and the wheel.
A various types of suspension systems is developed and applied to the vehicle, and one type of the suspension systems is a suspension system provided with multilinks which maximizes performance of high performance vehicles.
A rear-wheel suspension system of multilink type generally includes a wheel carrier rotatably supporting the wheel. A lower end portion of the wheel carrier is connected to a sub-frame of the vehicle body by using a lower control arm disposed along a width direction of the vehicle and is connected to the vehicle body by using a trailing arm disposed along a length direction of the vehicle.
In addition, an upper end portion of the wheel carrier is connected to the vehicle body by using two upper control arms disposed along the width direction of the vehicle.
The coil spring and the shock absorber are integrally or separately disposed along a height direction of the vehicle at a predetermined position of the lower control arm.
Accordingly, the load caused by bump and rebound of the vehicle is transmitted along movement traces of the lower control arm, the upper control arms, and the trailing arm, and the load is absorbed and reduced by shock-absorbing means consisting of the coil spring and the shock absorber.
The upper control arm 100 of the multilink suspension system, as shown in FIG. 7, has “U”-shape (that is, both ends thereof is positioned higher than a middle portion thereof) so as to prevent from being interfered with members of the vehicle body (e.g., side members of the vehicle body) disposed above the upper control arm 100. Particularly, most of a rear upper control arm 100 has the middle portion bent downwardly.
The upper control arm 100 is formed by assembling front and rear members 102 and 104 after the front and rear members 102 and 104 are manufactured by pressing steel plates. The front and rear members 102 and 104 are assembled with each other by a method such as welding. The upper control arm 100 as described above may be corroded by the foreign materials input into the upper control arm 100.
Jig holes 106 must be formed for manufacturing the front and rear members. If the upper control arm 100 is mounted at the vehicle, the foreign materials such as water and deicer are flowed into the upper control arm 100 through the jig hole 106. If there is no drain hole, the upper control arm 100 may be corroded. Further, in a case that corrosion fatigue occurs, the control arm may be broken during running the vehicle and deadly traffic accidents may occur.
In order to solve these problems, a conventional control arm is provide with a drain hole 108 formed at a lower middle portion such that the foreign materials fall downward and are exhaust through the drain hole 108 as shown in FIG. 8. Such a drain hole 108 can exhaust the foreign materials, but a cross-sectional area of the lower middle portion should be increased so as to bore the drain hole 108 with a sufficient size. Therefore, weight of the control arm may increase.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.